Night Vision Technique
How to Use Your Eyes at Night, How to Search at Night, Dark Adapting
Your Eyes, When to Put on Dark-Adaption Goggles, Protecting Dark-Adaption
with Red Light, Hints on Spotting Ships at Night, General Rules for Seeing at Night

section 1

Importance of Lookouts

A lookout is the "eyes" of his ship, As a lookout you
are charged with a heavy responsibility, which includes
that of seeing and reporting any enemy ship or plane
before he can attack, and of sighting and reporting
any menace to navigation before your ship enters the
danger area.

Your job is to sight objects, not only before anyone
else in the ship but also in time for all hands to man
battle stations before an attack develops, or for any
other action that may be necessary. Your ability to
sight and report the enemy before he can attack may
enable your ship to in an engagement with enemy
surface craft, sink an enemy submarine, or shoot down
attacking planes. On the other hand, inattention to
your lookout duties, or carelessness in performing them,
may easily cause the loss of the ship and the death of
your shipmates.

To serve both the offensive an defensive purposes
above suggested, you must have the "know how' involved
in carrying out your duties properly. Getting
the "know how" is the primary purpose of Lookout Training.

--3--

--4--

section 2

Physical Qualifications of Lookouts

VISION. The first and fundamental
physical qualification of a lookout is
good day and night vision. The ability
to sight objects during daytime, and
at night depends partly upon training,
and partly upon good vision. You must
have both to qualify as a competent lookout.

HEARING. Satisfactory hearing is a
requirement.
When visibility is at a minimum, as
during a heavy fog, keen hearing is tremendously important. Men posted
as fog lookouts can often hear sounds
from other ships, buoys, etc., before they
can see them. Training in recognizing
significant sounds at sea is important.

ENDURANCE. Keep in good physical
shape! A tired lookout is an invitation
to trouble for the whole ship. Fatigue
is sure to interfere with your night
vision. You owe it to your ship to be
at your best.

--5--

--6--

section 3

Lookout Positions

Lookouts are classified as follows:

Horizon lookouts are stationed high to obtain
maximum range of vision.

Surface lookouts are stationed in a well-protected
location as low in the ship as is physically
possible and as the condition of the sea permits,
from which they can see the surface of the sea.

Sky lookouts are stationed where they can best
see the whole sky.

In small craft the available men may have to combine
the duties of two kinds of lookouts, or even of all three.
All lookouts--in fact, all hands on board ship--report
everything they see, wherever it may be located.
Even the most harmless appearing object might be
hiding a periscope.

HORIZON LOOKOUTS. The horizon lookout is so
named because his first duty is to detect objects near or
beyond the horizon before they are visible from lower
positions in the ship.

On all ships it is essential that the horizon lookout
have the highest position practicable--for any part
of the ship that extends above his position may be
sighted by an enemy before the enemy becomes visible
to him.

--7--

SURFACE LOOKOUTS. Surface lookouts are so
named because their attention is concentrated on the
surface of the sea. They must report everything within
view, from the ship to their horizon, and they must be
able to detect and recognize a great variety of objects,
such as periscopes, torpedo wakes, mines, ships of all
types, buoys--even whales. They are stationed as low
in the ship as practicable in order to obtain the advantage
of seeing an object silhouetted against a
lighter sky background above a near horizon. This is
especially true at night.

Surface lookouts must search the sea rapidly and
with extreme thoroughness, because periscopes, mines,
and torpedo wakes may first be sighted close aboard.

--8--

SKY LOOKOUTS. Sky lookouts are so named because
they are responsible for the entire bowl of the
sky, from the horizon to directly overhead. They report
everything sighted including friendly and enemy planes,
flares, blimps, parachutes, rockets, and even shooting stars.

The sky lookout's job makes severe demands on the
eyes. Sky lookouts should search intently for brief
periods and then be relieved. For this reason they
should be organized in paris, one searching and the
other reading position angle and bearing, or acting as
a talker.

No matter was type of ship you are serving in--no
matter what your lookout duties are, never forget that:
WHEN YOU HAVE PICKED UP A TARGET DIFFICULT
TO SPOT, MAKE YOUR REPORT, BUT DO
NOT TAKE YOUR EYES OFF IT UNTIL YOU

--9--

KNOW IT HAS BEEN SEEN BY PROPER AUTHORITIES.
HOWEVER, AS SOON AS YOUR
REPORT OF A PLAINLY VISIBLE TARGET IS
ACKNOWLEDGED, RESUME SEARCH OF YOUR
SECTOR FOR NEW TARGETS.

The enemy is tricky. Sometimes he will try to sneak
in his main attack, gambling that you will have your
attention on a target already under fire. Don't let
him get away with it! Cover your area thoroughly at
all times--even in the midst of action--and don't be
distracted by anything, or your will be playing right
into his hands.

--10--

FOG LOOKOUTS. When a ship is running through
fog, it is in an extremely blind condition, and danger
from mines and collision is greatest. Fogs vary considerably
in thickness. Visibility may be only a few
hundred yards, or even zero. It often happens that a
fog thins, or even lifts above the surface of the water.
This enables lookouts stationed very low in the ship to
see much farther than lookouts stationed higher. One
or two fog lookouts are normally stationed at the bow.
They can see farther ahead than the bridge watch,
and also are better placed to hear other ships and thus
help prevent collision. For this reason, they report all
that is heard as well as all that is seen. On the other
hand, if there is a low, dense fog, it is practical to place
a lookout as high as possible; he can thus see farther
than would be possible at the bow.

--11--

--12--

section 4

What Every Lookout Must Know

A Skillful lookout spots and identifies objects on the
sea and in the air during all conditions of light and
weather. He also relays immediately the necessary
information to the proper place. Just sighting an object
is of no use unless it is called to the attention of those
responsible for bringing it under fire, or avoiding
torpedoes or bombs.

HOW TO REPORT. The officers in your ship depend
on the reports that you make to them when you
are on watch as a lookout to help them meet any
situation the ship may encounter.

PHONE EQUIPMENT. The entire efficiency of the
lookout system depends on speed in getting proper reports
to the right officers. Lookout stations are connected
with Control Stations by telephone. Adequate
communications must always be maintained.

--13--

THE CONTACT REPORT It is essential that every
object sighted be reported to the proper authority immediately.
This first, speedy report is called the
contact report. This reported gives two essential facts:

What your see.

Where you see it.

"What you see" is the shortest possible name of the
object you have sighted. Destroyer! Smoke! Cruiser!
Plane! Submarine! Mine! Battleship! Slick!
Buoy! Periscope! Object!

When you can't make out something you have
sighted, report it merely as an object, and at the close
of the report, say this: "Cannot make it out." In

--14--

Making Contact Reports, Never Hesitate While
You Try to Identify the Object You Have Sighted.
Report it immediately, giving it the proper name if possible,
and if not, calling it an object. By putting the
phrase "cannot make it out" at the end of the contact
report, you will avoid delay in giving your officers the
information essential to proper action.

"Where you see it" is the relative bearing and estimated
distance of the object you are reporting, as:

"Bearing zero-seven-zero, halfway to the horizon."

In contact reports of planes, position angle is included,
and is given after the bearing, often in place of
range, as:

"Bearing one-one-oh! Position angle, 10 degrees!"

Make your contact report in the fewest possible words
and in the shortest possible time! "What you see,"
and "Where you see it." Properly done, this will
give your officers the information they require in from
2 to 6 seconds from the time you have sighted an object.

THE AMPLIFYING REPORT. After the contact
report has been made, in order to give the officers more
complete information, a second report, the amplifying
report, is made. This report normally gives five items
of information:

Station called.

Station reporting.

What you see.

Where you see it.

What it is doing.

--15--

The first and second items simply call the report to
the attention of the officer concerned, and tells him who
is reporting. The third item tells what has been sighted.
The fourth and fifth items describe the location, and tell
what is happening.

ACKNOWLEDGING REPORTS. Be sure that your
reports are acknowledged. Only when you hear the
proper acknowledgment, can you be certain that your
report has been received. If the report was to Bridge,
the Bridge Talker should acknowledge, "Bridge, Aye,
Aye." If to Conn, the Conn Talker says: "Conn,
Aye, Aye; or to Air Defense Officer: "Air Defense,
Aye, Aye." If your report is not acknowledged, repeat
it. The station called may not get your report for various
reasons. For example, it is possible that phones are
being shifted or are even out of commission. After
repeating your report a second time and still receiving
no acknowledgment, make your report to another station
in the vicinity of the station called. Request that
the information be relayed. Get Your Reports Through!

REPORTING

Follow these rules:

Give your report in a clear, distinct voice.

Be sure your reports are acknowledged.

Use as few words as possible--what you see;
where you see it.

Give relative bearings and target angles in
regular Navy style.

--16--

section 5

What to Report

RELATIVE BEARINGS. Definition.--The relative
bearing of an object is the direction of the object measured
from the ship's heading. The ship is assumed to
be on course 000. The relative bearing is the angle
between the ship's course and a line to the object
measured clockwise form the bow, in degrees. The
horizon--the point where the sky and water seem to

Observe that 000 is always ahead and that the
degrees are always counted clockwise--that is, in the
same direction as the hands of a clock move. It may
be helpful to consider the bearing circle as the face of a
clock. The distance between each number is 30 degrees
(Figure II).

You must give the relative bearing in approved Navy
style. All relative bearings are reported by the use of
three numbers.

Examples as follow:

Written

Spoken

005

zero-zero-five

045

zero-four-five

180

one-eight-on

300

three-double-oh

207

two-oh-seven

030

zero-three-zero

IMPORTANCE OF PRACTICE. Learn the bearing
circle and then practice taking relative bearings on
everything you see. If, for example, you and your shipmate
are making a liberty and spot a couple of blondes
on the beach, take a bearing on them. Don't say that
there are a couple of blondes over there, but rather,
"Two blondes, bearing 045!" Constant practice will
help you be quick and accurate when it counts.

--19--

Figure III.--Relative Bearing and Target Angle Diagram

--20--

TARGET ANGLES. After some experience, lookouts
should learn to estimate target angles. This information
is of great value to the OOD, and much valuable
time can be saved if lookouts can proficiently estimate
this angle. The purpose of reporting target angles is
to tell the Officer of the Deck the approximate course
of the ship sighted. Don't let the title fool you Target
angles are reported on all ships--friend or foe.

Target angle is measured clockwise from the course
of the target to the line of sight of your own ship. In
other words, Target Angle is the relative bearing of
your ship as seen from the target. Target angles are
reported in degrees.

See Figure III for examples.

DISTANCE. A knowledge of how to estimate ranges is

--21--

Figure IV.--Position Angle DIagram

--22--

essential. Range is usually reported in units of miles or
yards. however, the distance to an object relative to
the horizon, such as "one quarter of the distance to th
horizon," "half the distance to the horizon," etc., or
"close aboard," or "hull down," are all descriptive of
the distance of an object. The latter method can be
more readily learned and eliminates a considerable
amount of guesswork. Tables and curves are available
to assist you in estimating the ranges of objects visible
from different heights. Study them and apply your
knowledge at any and every opportunity in order to
develop your ability in estimating ranges. Estimate
ranges whenever you get a chance, and compare your
estimates with the actual range whenever possible.
You can thus develop real ability to judge range accurately.

POSITION ANGLE. As a sky lookout, it is your duty
to search an assigned sector of the sky, and to report
everything sighted in it to the proper stations. In order
to do this effectively you must give more than just a
relative bearing of a sighted plane. You must also report
the position angle.

The lookout's line of sight is aimed above the horizon,
making a vertical angle with it. This angle is nown
as the position angle, sine it gives the exact position
of the plane above the horizon. (See Figure IV.)

You can describe the vertical location of a plane by
reporting the position angle in degrees. The point

--23--

directly overhead is the zenith. The zenith is position
angle 90 degrees. Position angle is always measured
from that portion of the horizon nearest the
plane. Thus, no position angle will ever exceed 90
degrees. When a plane has passed overhead, its
position angle is measured from the portion of the
horizon which you see directly below it, once it passes
the zenith it is no longer measured form that part of the
horizon from which it came.

As the plane approaches from the horizon at constant
speed and altitude, the position angle increases very
slowly until the plane reaches a position angle of about
25 degrees. Then the position angle increases more
and ore rapidly. A plane flying toward you at constant
speed and altitude seems to rise quickly.
Actually, it does not rise, but only appears to, due to
the increase in position angle.

The plane must be spotted and reported while it
is still some distance from the ship, since it takes a
battery several seconds to get into action, and since it
also takes time for shells to reach the plane.

Experience has shown that a modern bomber must
be spotted before it reaches a position angle of about
25 degrees, if the plane is to be shot down or forced to
turn away before it reaches the release point of 55 degrees.
After this it is too late to stop the plane form
dropping its bombs. Sighting, reporting, shooting, and
hitting must be completed before the bombs are released.

--24--

section 6

Equipment for Lookouts and Its Use

CARE AND USE OF BINOCULARS. Binoculars are
fragile gadgets--they get out of which when handled
roughly or carelessly. Take care of them--the day
will come when you will need badly all the help they
can give you. They cost a lot of money, and they are
scarce, as not enough can be made to equip all those
who should have them.

Follow these suggestions:

Always use the neck strap.

--25--

Hold the binoculars against your chest when
you lean over.

Don't let them strike against anything.

DOn't leave binoculars in the sun.

Keep the binoculars in the case when not in use.

Don't expose binoculars to sudden, extreme
change in temperature.

Keep your binoculars clean

Use lens tissue. If available, use lens-cleaning liquid according to directions.

Don't use your sleeve or anything that contains grit or grease.

Don't blow on the lenses in below-freezing weather--the
moisture will make a skating ring and you won't be able to see.

Most binoculars have two adjustments, the interpupillary
adjustment and the eyepiece adjustment.
Bend the binoculars so that the eyepieces are the same
distance apart as the pupils of your eyes. If this adjustment
is not properly made you will see something
like this ;
when made correctly you have a single
visual field, and it appears like this .
Practice making this adjustment several times and when you are
sure you have done it correctly--note the number on
the hinge, and always remember it! It is a good idea
to have the medical officer measure the distance between

--26--

the pupils of your eyes, to ensure a correct adjustment.

The second adjustment is on each eyepiece. Start
with the setting at +4. Close one eye and turn
the eyepiece until the object your are observing is
clear and distinct. Not the number that gives
you this adjustment. Then do the same for the other
eye. Remember these
numbers! Because our day and night eyes differ,
this focusing has to be done both for daylight and for
the dark. Most likely your night focus will be one to one
and a half minus from your day focus.

It is most important that you remember both adjustments.
You won't have time when going on watch to
experiment and find the proper settings.

When using binoculars hold them against your eyebrows.
At night look at the bottom of the binocular
field--it is a fact that you can see better that way!
Use your binoculars for night scanning! See pages
35, 36, and 37.

It may be that at some time you will be forced to use
binoculars that are out of collimation. This means
that the two barrels and the hinge are not absolutely

--27--

parallel, as they are supposed to be. An expert optical
repairman can fix them--but don't you monkey around!
However, even binoculars that are not properly collimated
are not entirely useless. Make your regular
adjustments, but turn the binoculars so that you use
just one eye--like a telescope.

By taking good care of your binoculars and using
them correctly you can guard your life and the lives of
your shipmates.

ALIDADE. Binoculars for surface lookouts are usually
mounted on an alidade, which indicates bearings in
degrees. Horizontal motion of the binoculars is transferred
through a shaft to a bearing indicator below.
A dial follows the horizontal movement of the binoculars,
and gives in degrees the exact bearing angle.

To take bearings at night, a red light provides a dim illumination.

PELORUS. On some ships the lookout may use a
pelorus to take bearings. The pelorus has two sighting
vanes on opposite sides of a pivot. These sighting
vanes are lined up with the object observed, and the
bearing is read through a slot in the army carrying the vanes.

Warning on Night Use of Pelorus:

Do not permit light in pelorus to show brightly.

Always turn off when not in use.

Never turn on when in area of possible enemy aircraft.

--28--

POSITION ANGLE INDICATOR. The elevation
(position angle) of an approaching airplane is measured
with a position angle indicator which may be attached
to the binoculars. It consists of a ball that rolls in a
cured path, and indicates the angle of the binoculars
to the horizon. When the glasses are pointed horizontally--at
the horizon--the ball is at rest at zero
degrees. As the binoculars are raised above the
horizon, the ball rolls back and indicates the angle.
The relief lookout reads the position angle, while the
lookout keeps the approaching plane centered in the field.

Sky lookouts may have special supports secured to the
deck and arranged to permit search through binoculars
from the horizon to a position angle of 40 degrees. The
type of support may vary from vessel to vessel. For the
additional sweep to the zenith, the naked eye is used.

GOGGLES To protect
lookouts' eyes from wind and weather and to adjust the
intensity of light reflected from the water and from
sunlit clouds, lookouts use goggles. They are light
green, ground and polished. Since it is difficult to use
both goggles and binoculars, binoculars are fitted with
easily removable filters of the same color as the goggles.

. . . have the medical officer measure the distance between
the pupils of your eyes

--29--

A type of goggle used by some lookouts is the variable
density polaroid goggle. The lookout can adjust them
to admit a comfortable amount of light, regardless of the
brightness of the part of the sky he is searching. By
adjusting the goggles to their greatest degree of density
he can search the area around the sun with perfect ease.
However, goggles should never be adjusted "to dark"
as the range of visibility of objects would be decreased.

DARK-ADAPTATION GOGGLES. Put on dark
adaptation goggles at least 30 minutes before going on
watch. If possible avoid exposing your yes to any
white light, by putting goggles on immediately upon
being awakened. They adapt your eyes to darkness,
even while you wear them in a room with bright, white
lights. While you are on night duty, if it is necessary
for you to look at anything under a white light, or visit
a lighted room such as the chartroom, always put your
dark adaptation goggles on first.

. . . be sure to dress warmly at all times

CLOTHING. Lookouts are often
exposed to bad weather. For this reason, you are provided with
especially designed clothing and equipment, which give extra
protection. Be sure to dress warmly at all times, as it will
help keep your efficiency as a lookout at a maximum.

--30--

section 7

Proper Methods of Search

SCANNING. If your are going to be a good lookout,
you need more than a good pair of eyes, a good pair of
binoculars, and a place from which you can look.
You must also know how to look!

Did you ever watch a person's eyes while he was
reading? If so, you observed that the eyes moved in
jerks. That is the way you scan your sector when

--31--

standing lookout watch. Our eyes see better using
this method.

It is important that you search your assigned area
according to some system. Things happen too fast to
use a hit-or-miss method--you get hit, and miss the enemy.
Don't sweep the horizon! Use a step-by-step
method. Start at the extreme left or right of your sector,
move your binoculars 5 degrees into the sector, pause
for about a second, move another 5 degrees, pause
again. Continue until you have completed your
sector. Then sweep back to the starting point and proceed
as before. By using this method you cover your
search area thoroughly and quickly.

At night, look at the bottom of the binocular field
and search in a slow continuous sweep. Remember
this in connection with pages 25, 26, and 27.

SKY LOOKOUTS--SCANNING. All lookouts use the
step-by-step method of search but the sky lookout must

--32--

apply it somewhat differently, since he must search
vertically as well as horizontally, and his methods of
search depend on cloud conditions. The method laid
out below is based on the fact that a good lookout can
sight planes at 6,000 yards with his naked eye, and at
two or three times that range with binoculars.

The eye is much quicker and covers a much larger
field than binoculars. It should be used unaided
whenever and wherever, because or cloud conditions,
planes can only be sighted within the range of visibility
of the naked eye. Thus, if the sky is overcast at
2,000 feet, planes will be readily sighted with the naked
eye at position angles over 6 degrees and binoculars
should not be used above this angle. On the other hand
in a cloudless sky the sweep with the binoculars must
be extended up to 30 degrees position angle in order to
ensure sighting planes flying at high altitude.

CLOUDLESS SKY. 1. Sweep are of 0 degree to 30
degrees position angle in your sector with your binoculars
by successively increasing position angle in
5-degree steps. After each complete sweep drop your
binoculars and rest your eyes briefly by sweeping higher
position angles with the naked eye.

2. On cloudless days your eyes will tend to lose distant
focus, and may focus on a point a short distance
away. When this occurs it will be most difficult to
pick up a plane in clear sight. Remember this and
occasionally glance at clouds, distant ships, objects,
etc., to refocus your eyes.

--33--

PARTLY CLOUDY. 1. Search 0-degree to 30-degree
arc with binoculars as before; then sweep edges of
clouds up to about 50 degrees.

2. As clouds increase in number operate as for overcast conditions.

LOW OVERCAST. 1. Sweep your sector with binoculars
for 3 degrees of position angle for every 1,000 feet
height of overcast. Thus, for overcast at 3,000 feet
sweep with binoculars only to 9 degrees or 10 degrees.
Maintain sharp watch with the naked eyes up to 50
degrees position angle.

HIGH OVERCAST. 1. Use the procedure for low
overcast up to height of clouds of 10,000 feet. Above
that use procedure for cloudless day.

SURFACE LOOKOUTS. The surface lookout uses the
step-by-step method of search in practically the same
way as it is used by the horizon lookout. However, as
a surface lookout, you must search the entire surface of
the sea from very near your ship to the horizon.

Search the entire surface by moving your binoculars
in a horizontal path, pausing each 5 degrees. This
step-by-step method of search gives your eyes a chance
to detect any object which does not fit into the whole
picture. You will soon become accustomed to using
this search pattern, and you will find that with it you
can cover a wide area in a short time.

--34--

section 8

Night VIsion Techniques

HOW TO USE YOUR EYES AT NIGHT. The business
of being a lookout requires that your learn two
methods of seeing which are quite different. Daylight
searching uses the step-by-step method. In this method,
the eyes are focused in a series of brief steps on certain
areas or objects.

For night searching you must learn a brand new
method which may seem strange at first.

HOW TO SEARCH AT NIGHT. When you look
directly at the horizon on black nights, the horizon
immediately in front of your eyes is actually not seen.
Any object lying in this region will escape detection.
This fact is very little appreciated by civilians, but it is

--35--

one of the most important facts to an expert lookout
searching at night.

The recommended technique of night scanning consists
of the following: The lookout directs his eyes at
levels about 10 degrees above or below the horizon.
He does not sweep his eyes evenly over the area for
which he is responsible, but moves them in short jumps
of about 10 degrees to 15 degrees, with momentary
fixation pauses, to search the sky or horizon systematically
and to be alert for objects in the "corners of the
eyes." This may involve slight movements of the head
as well as movements of the eyes. The lookout should
be cautioned to direct his vision in quick jumps with
short fixation pauses, and not keep staring at any one
place for a long period of time. Nothing can be seen
while the eyes are actually in motion, but they are most
sensitive just after being moved. When an object is
suspected in a particular area, the lookout should
"scan" this area, moving his eyes in short jumps from 10
degrees on the right side of the objects to 10 degrees
above, to 10 degrees on the left side--until more complete
identification is made. This technique does not come
naturally to most people, and therefore must be practiced

You find that you are almost blind for a few minutes

--36--

conscientiously. Your "night eyes" are sensitive
to very dim light, but they are even more sensitive to
motion. Therefore, your night eyes detect moving
objects much ore readily than they detect stationary ones.

As you know, when using binoculars in the daytime,
you look straight through them. But when using
binoculars on dark nights, a different method is necessary.
Hold them up to your eyes, but direct your gaze
downward, below the binocular field. You will find
that you can see more clearly this way, because of the
peculiar characteristics of night vision.

DARK ADAPTING YOUR EYES. If you were to go
on night watch direct from a lighted compartment, you
would find that you would be almost blind for a few
minutes. Gradually your vision would improve as your
eyes became accustomed to weak light. After 10
minutes, you would be able to see fairly well. It would
take 30 minutes, however, before you would reach your
best night vision. This improvement of vision in
dim light is adaptation to darkness usually called
dark adaptation."

An improved method of adapting your eyes to darkness
is to wear special red goggles for half an hour
prior to going on watch. They adapt your eyes to
darkness while you wear them.

The goggles with which they Navy supplies you are
especially designed for adaptation. While wearing

--37--

them under ordinary white light, you can play
games, write letters or read almost as comfortably as
you could without them.

Although you have worn dark-adaptation goggles
half an hour before going on watch, it still takes at least
5 minutes more in darkness before you have developed
your best night vision. Therefore, never relieve the
watch until you have actually been at your station in
actual darkness for at least 5 minutes. This is in
addition to the 30-minute period during which dark-adaptation
goggles are worth.

WHEN TO PUT ON DARK-ADAPTATION GOGGLES.
When you are awakened for a night watch,
put on your dark-adaptation goggles immediately, even
before you open your eyes. This prevents your eyes
from losing the adaptation to darkness which they have
acquired while they were closed during sleep. If it is
necessary for you to visit a lighted compartment, or
look at anything under any but red light, always put
on your dark-adaptation goggles first.

PROTECTING DARK ADAPTATION WITH RED LIGHT.
Quartermasters have to make numerous entries
in their notebooks during night watch. If these
entries just be made on the bridge the light from a
flashlight with a red lens will give sufficient illumination.
Never use a white light, for it will destroy your dark
adaptation. Of course no one should ever use any

--38--

flashlight--red or white--in such a way that the enemy
could glimpse its direct light, or even its light reflected
from some object.

HINTS ON SPOTTING SHIPS AT NIGHT.
As a good lookout, you must know how enemy ships are apt
to disclose themselves. For example, when the moon
is either rising or setting, a ship which happens to cross
between you and the moon will be silhouetted for a
short time. In much the same way, a ship passing
between you and coastal lights may disclose itself by
blocking out a portion of them.

Watch reflections of the moon or a bright star. A
ship crossing the path of reflected light will appear as a
dark object which interrupts the normal motion of the
light reflected from the waves.

. . . while wearing them you can read, write, play games . . .

On a night "so black that you cannot see your hand
in front of your face," it is still possible to detect ships
by the phosphorescence they stir up. Phosphorescence is
often very prominent in the bow wave, in the wash alongside
the ship, and in the wake. Very often, single
flashes of light may be caused by a distant ship
striking a patch of very bright phosphorescence.

--39--

Under certain conditions a distant fog bank or a low
lying bank of clouds may appear lighter than the water
or sky. When this occurs, a ship may be silhouetted
against it.

Under different conditions, a ship may pick up enough
light from stars or moon to appear as a light object
against a very dark background. You will see such
ships only when the moon or bright stars are in back of
you, since only at this time will enough light strike the
side of the ship visible to you.

GENERAL RULES FOR SEEING AT NIGHT. The
experienced lookout knows how to use the brain as well
as the eyes. As a lookout, your value to your ship will
depend on remembering and using the following important rules:

Keep in good physical condition. Fatigue is
sure to interfere with your night vision.

--40--

section 9

Identification of Ships and Aircraft

The identification of ships and aircraft deals with the
different types, classes, and structures. To be able to
identify a ship means to be able, first, to tell whether or
not it is a ship--as distinguished from other visible
objects such as islands, rocks, or trees or buildings

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ashore; second, to be able to tell what type of ship it is--whether
it is a battleship, a cruiser, a destroyer, some
type of auxiliary vessel, etc.; third, to be able to tell
whether it is a ship of our own fleet, that of an ally, or
that of the enemy; fourth, to be able to tell in which
direction the ship is moving in relation to your own ship,
or whether or not the ship is still--by considering certain
features of that ship. The importance of this subject to
the lookout cannot be stressed too highly, and much
time and effort should be spent by all lookouts in studying
the many pamphlets and training aids available on
this subject. Identification material is not included in
this manual in view of the excellent material already available.

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section 10

Spotting Submarines

The very nature of the submarine makes it difficult to
detect, and makes its attacks extremely deadly. The
submarine has a long, low, and narrow hull. The
conning tower, which is the navigating bridge when the
submarine is surfaced, is the only prominent structure
above the hull.

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PERISCOPES. A modern attack periscope is no larger
than a swab handle, and need be exposed no more than
a few inches in calm seas. It is normally raised only
when the submarine is traveling at very low speed,
when the periscope will leave almost no wake. When
the submarine is making sufficient speed the periscope
caused a very noticeable wake, or streak of foam, which
is called a feather because of its white and featherlike
appearance.

The attack periscope is so difficult to spot that the
lookout must be extremely alert to see it.

Submarines may have an armament of one or two
guns of moderate size--from 3 to 6 inches--usually
located on the deck, forward or abaft the conning tower.
In addition to these guns, one or more antiaircraft
machine guns may be mounted. Many foreign submarines
have their guns mounted on a forward extension
of the conning tower, well above the deck.

If you sight what looks like a small boat bow-on, or
stern-on, at a distance, look it over sharply, for it ay
be the conning tower of a submarine running awash.
"Awash," of course, means that the submarine is running
with its deck just below the surface while the conning
tower projects above German submarines generally
operate at night while awash. By cruising this
way, they are able to obtain air for diesel operation,
and are in a position to make a crash dive.

A submarine making a periscope attack will expose
its periscope for only about 10 seconds at a time. Every

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suspected feather should be reported, even though it
disappears immediately. When a periscope is moving
to leeward, the telltale feather is quite likely to be absent
or unnoticeable, since the periscope is moving with the
waves. This makes it even more difficult to spot the submarine.

Many submarine attacks must be made on short
notice. Therefore, they may come from any quarter.
For this reason, you must always be alert to detect a
periscope, whatever the direction of your search.

Submarine attacks are most likely to come in the bow
sectors from 300 across the bow to 060. Lookouts cover
assigned sectors irrespective of type of ship or nature
of duty. These sectors on the bows of ships convoyed
are the most vital.

On the surface the submarine is much less conspicuous
than surface ships of comparable size. This is due,
of course, to the low deck and small conning tower.
When a submarine tends to blend with the water, a
lookout in a low position often can see it silhouetted
against the sky. Submarines often have been spotted

--45--

at night by members of the crew on deck. Remember
this every time you go topside.

At night, submarines often lay to with their decks awash
while charging batteries. If the sea is not too rough, they
may cruise with the decks awash. In this condition, a
submarine can make a crash dive in a matter of seconds.
A submarine awash presents
a very small target, and this makes a lookout's
job still more difficult. When awash, a submarine
often has a long streak of foam both forward and abaft
the conning tower. On very dark nights, this foam
may be more visible than the conning tower itself.

Submarines may sometimes reveal themselves by
unintentional signs. One of these is oil slick, from a
leak due to damage from depth charges, or from some
other cause. Since small oil slicks break up rapidly in
moderate seas, you must report instantly every slick in
sight. Flocks of gulls may signal the presence of a
submarine. They sometimes follow the faint shadow
of the submarine in the same way they follow schools
of small fish. Therefore, always report any unusual
gathering of gulls.

A submerged submarine can identify itself to friendly
ships by releasing a recognition signal which rises

--46--

quickly to the surface, where it ignites and gives off
colored smoke. One type fo signal, on breaking water,
fires a smoke bomb 1 or 2 hundred feet into the air,
where it explodes. Lookouts must be very prompt in
reporting such recognition signals, and should report
the color at once.

TORPEDOES. The underwater projectile of the submarine
is the torpedo. Torpedoes, other than electric,
form a wake or streak of foam on the surface, caused
by gas bubbles released by the torpedo during its run.
The torpedo may be set to travel at various speeds and
depths. The speed varies, and may be as high as 50
knots. Since the gas bubble rise to the surface slowly,
a torpedo may be running more than a hundred yards
ahead of the wake which appears on the surface.
Since the torpedo runs so far ahead of its wake, the
lookout has very few seconds to report a sighted wake
if his ship is to maneuver to avoid the torpedo. Here, if
ever, seconds count.

Even though you know how submarines may look
under different conditions, spotting them is still your
toughest job. You can never know too much about it.

You can search the sun's reflection for submarines by
wearing goggles. Under these conditions of great light
contrast, the submarine appears in silhouette. On
moonlight nights, the path of the moon's reflection should
be watched on the chance that a surfaced submarine
may be spotted.

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You may never see more than one or two submarines.
When you do see one, or its periscope, or a periscope
feather, the safety of your ship, as well as the chance to
destroy a deadly enemy, will depend on its instant recognition.

Conclusion

The hints contained in this manual can aid you to
become more proficient in your job as a lookout. Read
them frequently, studying them, and apply them whenever
possible. Remember that your ability as a lookout
may mean the difference between a major victory and a
bitter defeat.